Question

I am using Perl to do text processing with regex. I have no control over the input. I have shown some examples of the input below.

As you can see the items B and C can be in the string n times with different values. I need to get all the values as back reference. Or if you know of a different way i am all ears.

I am trying to use branch reset pattern (as outlined at perldoc: “Extended Patterns”) I am not having much luck matching the string.

("Data" (Int "A" 22)(Int "B" 1)(Int "C" 2)(Int "D" 34896)(Int "E" 38046))
("Data" (Int "A" 22)(Int "B" 1)(Int "C" 2)(Int "B" 3)(Int "C" 4)(Int "B" 5)(Int "C" 6)(Int "D" 34896)(Int "E" 38046))
("Data" (Int "A" 22)(Int "B" 22)(Int "C" 59)(Int "B" 1143)(Int "C" 1210)(Int "B" 1232)(Int "C" 34896)(Int "D" 34896)(Int "E" 38046))

My Perl is below, any help would be great. Thanks for any help you can give.

if($inputString =~/\("Data" \(Int "A" ([0-9]+)\)(?:\(Int "B" ([0-9]+)\)\(Int "C" ([0-9]+)\))+\(Int "D" ([0-9]+)\)\(Int "E" ([0-9]+)\)\)/) {

    print "\n\nmatched\n";

    print "1: $1\n";
    print "2: $2\n";
    print "3: $3\n";
    print "4: $4\n";
    print "5: $5\n";
    print "6: $6\n";
    print "7: $7\n";
    print "8: $8\n";
    print "9: $9\n";

}

Answer 1

Don’t try to use one regex a set of regexes and splits are easier to understand:

#!/usr/bin/perl

use strict;
use warnings;

while (<DATA>) {
    next unless my ($data) = /\("Data" (.*)\)/;
    print "on line $., I saw:\n";
    for my $item ($data =~ /\((.*?)\)/g) {
        my ($type, $var, $num) = split " ", $item;
        print "\ttype $type var $var num $num\n";
    }
}

__DATA__
("Data" (Int "A" 22)(Int "B" 1)(Int "C" 2)(Int "D" 34896)(Int "E" 38046))
("Data" (Int "A" 22)(Int "B" 1)(Int "C" 2)(Int "B" 3)(Int "C" 4)(Int "B" 5)(Int "C" 6)(Int "D" 34896)(Int "E" 38046))
("Data" (Int "A" 22)(Int "B" 22)(Int "C" 59)(Int "B" 1143)(Int "C" 1210)(Int "B" 1232)(Int "C" 34896)(Int "D" 34896)(Int "E" 38046))

If your data can stretch across lines, I would suggest using a parser instead of a regex.